Microchip Technology 1N5252B (DO-35)

Overview

1N5252B (DO-35) from Microsemi is a 500 mW glass axial-leaded Zener diode with nominal Zener voltage 24 V ±5%, 5.2 mA test current, 600 Ω maximum Zener impedance at IZK = 0.25 mA, and temperature coefficient +0.088 %/°C. It regulates voltage in low-power reference and protection circuits across industrial control and instrumentation systems.

For engineers reviewing the 1N5252B datasheet, 1N5252B pinout, 1N5252B application, or 1N5252B equivalent, key selection criteria include Zener voltage tolerance, dynamic impedance at low test current, thermal resistance (310 °C/W on FR4), reverse leakage at rated VR, and DO-35 mechanical compatibility for through-hole mounting.

Technical Context

This device operates as a two-terminal voltage reference with cathode band marking polarity. It delivers stable regulation over -65 °C to +175 °C, with forward voltage ≤1.5 V at 200 mA and reverse leakage ≤0.1 μA at VR = 19.2 V (80% of VZ).

Zener impedance is measured using 60 Hz AC superimposed on DC bias (IZT = 5.2 mA), ensuring sharp knee characteristics per MicroNote 202. Thermal derating begins at 50 °C lead temperature or 25 °C ambient when mounted on FR4 with specified copper pad geometry.

Key Specifications

Pinout & Package

Hermetically sealed axial-lead glass DO-35 (DO-204AH) package with tin-lead or RoHS-compliant matte-tin plating; cathode identified by color band; weight 0.2 g.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar Zener voltage regulation applications.

Compared with 1N5252B, 1N4749A offers higher power headroom and lower impedance but requires board rework for DO-41 pads, while MMBZ5252BS enables SMT assembly at the cost of reduced thermal margin and absolute power capability.

Availability

1N5252B (DO-35) is available at Aetrix Electronics and suitable for industrial control panels, sensor signal conditioning circuits, and portable test equipment requiring stable component supply with consistent Zener voltage tolerance and thermal performance.

Supply support for 1N5252B (DO-35) includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Microsemi (now part of Microchip Technology) is a U.S.-based semiconductor company specializing in high-reliability analog and mixed-signal components for aerospace, defense, and industrial markets.

The 1N52xxB series was designed for ruggedized voltage regulation in mission-critical systems, emphasizing radiation hardness, wide temperature operation, and JEDEC-standardized parametric consistency across military and commercial variants.

FAQ

What is the maximum reverse leakage current for 1N5252B at its rated Zener voltage?

The maximum reverse leakage current for 1N5252B is 0.1 μA when measured at VR = 19.2 V (80% of nominal 24 V Zener voltage). This value is guaranteed per the datasheet's electrical characteristics table and reflects worst-case leakage under specified test conditions at 25 °C ambient temperature. The 1N5252B maintains this ultra-low leakage across its full operating temperature range, supporting high-impedance bias networks in precision analog circuits.

Does 1N5252B require heatsinking in typical PCB applications?

No, 1N5252B does not require external heatsinking in typical applications. Its thermal resistance is specified as 310 °C/W junction-to-ambient when mounted on FR4 with 4 mm² copper pads and 1 mm track width. At its rated 500 mW dissipation and 25 °C ambient, junction temperature rise is ~155 °C - well within its -65 °C to +175 °C operating limit. Derating begins above 50 °C lead temperature, but standard layouts meet thermal requirements without added heatsinks. The 1N5252B is optimized for self-contained thermal performance in compact through-hole designs.

How does the temperature coefficient of 1N5252B affect its regulation accuracy over temperature?

The temperature coefficient of 1N5252B is +0.088 %/°C, meaning its Zener voltage increases by approximately 21.1 mV per 10 °C rise above 25 °C. Over a -40 °C to +85 °C range, this results in ±1.17 V total drift from nominal 24 V. For applications requiring tighter regulation, this drift must be compensated using matched resistors or external circuitry. The 1N5252B's predictable, monotonic TC enables accurate first-order correction - a key reason it remains preferred in calibrated instrumentation where long-term stability outweighs absolute initial tolerance.

Can 1N5252B be used as a replacement for 1N4749A in existing designs?

No, 1N5252B is not a direct replacement for 1N4749A due to differences in power rating (500 mW vs. 1 W), package (DO-35 vs. DO-41), and Zener impedance (600 Ω vs. 20 Ω at higher test current). While both regulate at 24 V ±5%, the 1N5252B cannot handle the same continuous current or thermal load. Substituting 1N5252B into a 1N4749A design risks thermal runaway or regulation failure under load. The 1N5252B is best applied where its specific DO-35 form factor, radiation hardness, and low-leakage traits are required - not as a generic drop-in alternative.

Is RoHS compliance available for 1N5252B, and how is it designated?

Yes, RoHS compliance is available for 1N5252B via the "e3" suffix, resulting in the orderable part number 1N5252Be3. This variant uses RoHS-compliant annealed matte-tin plating instead of traditional tin-lead, meeting EU Directive 2011/65/EU requirements. The e3 version retains identical electrical specifications, DO-35 packaging, and mechanical dimensions as the standard part. Microsemi confirms solderability per MIL-STD-750 Method 2026, and the 1N5252Be3 is rated for 260 °C for 10 seconds - fully compatible with standard lead-free reflow profiles.